(Radiographics. 2002;22:323-336.)
© RSNA, 2002
Postoperative Anatomic and Pathologic Findings at CT Following Gastrectomy1
Kyoung Won Kim, MD,
Byung Ihn Choi, MD,
Joon Koo Han, MD,
Tae Kyoung Kim, MD,
Ah Young Kim, MD,
Hyun Ju Lee, MD,
Young Hoon Kim, MD,
Joon-Il Choi, MD,
Kyung-Hyun Do, MD,
Hyo Cheol Kim, MD and
Min Woo Lee, MD
1 From the Department of Radiology and the Institute of Radiation Medicine, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Gu, Seoul 110-744, Korea; and the Clinical Research Institute, Seoul National University Hospital, Seoul, Korea. Presented as an education exhibit at the 2000 RSNA scientific assembly. Received August 27, 2001; revision requested October 9 and received December 7; accepted December 20. Address correspondence to B.I.C. (e-mail: choibi@radcom.snu.ac.kr).
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Abstract
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Helical computed tomography (CT) is useful in identifying postoperative anatomic changes, complications, and tumor recurrence in gastric cancer patients who have undergone gastrectomy. Postoperative anatomic changes can usually be identified on consecutive CT scans. Complications include anastomotic leakage, duodenal stump leakage, intraabdominal bleeding, wound complications, and other less common complications (postoperative pancreatitis, retention of surgical foreign bodies, diffuse peritonitis). The degree and extent of bowel wall thickening is important in diagnosing tumor recurrence; however, CT lacks specificity. Large or conglomerated lymph node metastases can be easily diagnosed at CT; however, small solitary or focal metastases may not be detected or differentiated from nonmetastatic nodes. Ascites, a common finding with peritoneal seeding in gastrointestinal tumors, is well depicted at CT. Hematogenous metastases from gastric carcinoma are most frequently seen in the liver and are best demonstrated with helical CT performed during the portal venous phase of enhancement (sensitivity >90% for the detection of lesions >1 cm). The sophisticated surgical procedures used in gastrectomy can alter normal anatomy and make image interpretation difficult; thus, familiarity with the appearance of postoperative anatomic changes, complications, and tumor recurrence is essential for accurate CT evaluation of affected patients.
© RSNA, 2002
Index Terms: Stomach, CT, 72.1211 • Stomach, neoplasms, 72.321, 72.33 • Stomach, surgery, 72.45 • Surgery, complications, 72.458
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LEARNING OBJECTIVES
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After reading this article and taking the test, the reader will be able to:
- Discuss optimal CT technique for evaluation of patients who have undergone gastrectomy.
- Describe the CT appearance of postoperative changes following gastrectomy.
- Discuss the various patterns of postoperative complications and tumor recurrence in affected patients.
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Introduction
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Carcinoma of the stomach is one of the leading causes of cancer mortality worldwide. Complete resection of a gastric tumor and adjacent lymph nodes offers the only chance for cure (1,2). Early treatment has a better outcome than treatment of symptomatic individuals with more advanced disease (3). The evolution and increasing effectiveness and widespread use of screening for gastric carcinoma—particularly in the East—have resulted in earlier diagnosis and better prognosis for affected patients by increasing the chance for a surgical cure. However, they also require that radiologists be familiar with the typical postoperative imaging findings to ensure accurate evaluation of these patients.
Computed tomography (CT) is frequently used for postoperative evaluation of patients with gastric carcinoma. With the recent advent of helical CT, the role of CT has become pivotal in evaluating postoperative complications prior to radiologic intervention and in determining the presence of recurrent tumors and their response to chemotherapy. However, compared with the large number of articles describing postoperative complications and tumor recurrence following colectomy for colorectal carcinoma or the Whipple procedure for periampullary cancer, relatively few reports have focused on CT findings following gastrectomy (4–6).
In this article, we review technical considerations in CT used to assess patients who have undergone gastrectomy, discuss and illustrate postoperative CT anatomic changes following gastrectomy, and review the spectrum of postoperative complications (eg, anastomotic leakage, duodenal stump leakage, intraabdominal bleeding, wound complications) and tumor recurrence (local recurrence, lymph node metastases, peritoneal seeding, hematogenous metastases).
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Technical Considerations
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Modern CT scanners with high spatial and contrast resolution are ideally suited for postoperative abdominal imaging of patients who have undergone gastrectomy. However, the information gained from such an examination will depend on the skill and experience of the radiologist who must monitor and tailor the procedure. In general, CT scans obtained in the early postoperative period are unlikely to show recurrent tumor but are indicated for evaluation of surgical complications. Use of water-soluble contrast material is critical for evaluation of intraperitoneal leakage from the anastomotic segments. As a rule, postoperative abdominal CT should include contiguous sections from the dome of the diaphragm to the pelvic floor. This approach is warranted because many postoperative complications, particularly abscesses and fluid collections, are not localized to the surgical field (7). On the other hand, CT is frequently used for abdominal screening for the presence of recurrent disease. In such cases, intravenous administration of contrast material is mandatory for early identification of the recurrent tumor. In addition, opacification of the gastrointestinal tract is important for differentiation between bowel loops and intra- or retroperitoneal lymphadenopathy and can be achieved with oral administration of diluted barium sulfate.
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Postoperative Anatomy
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Billroth I gastroduodenostomy, Billroth II gastrojejunostomy with a Roux-en-Y or loop-type gastrojejunostomy, and total gastrectomy with one of these types of esophagojejunostomy are most commonly used to restore enteric continuity at gastric surgery for the treatment of malignancy (8,9). In Billroth I gastroduodenostomy, a partial gastrectomy (antrectomy) is performed, and continuity is maintained between the remnant stomach and duodenum by means of an end-to-end anastomosis (Fig 1a). The entire incised end of the stomach may be used for the anastomosis (Polya procedure), or only a portion of the lumen may be used and the remainder closed (Hofmeister modification). In the latter procedure, partial closure of the cut end of the stomach usually involves the lesser curvature aspect, and the anastomosis is created on the greater curvature side (Fig 1a). In Billroth II gastrojejunostomy, the duodenal stump is closed and an anastomosis is created between the remnant stomach and the jejunum. The type of anastomosis (Polya procedure or Hofmeister modification), the type of gastrojejunostomy (Roux-en-Y or loop-type, the latter in either an isoperistaltic or antiperistaltic configuration), and the placement of the anastomotic loop (retrocolic or antecolic position) may vary depending on the clinical situation and the surgeon’s preference. Because retrocolic gastrojejunostomy creates a shorter afferent (blind) loop than does antecolic gastrojejunostomy, it results in better nutritional status and less postoperative retrostomal herniation and is, therefore, usually performed whenever feasible (Fig 1b) (2). However, antecolic gastrojejunostomy is frequently performed in patients with advanced gastric cancer to keep the anastomosis out of the lesser sac, where recurrence usually first occurs (Fig 1c) (10). In addition, side-to-side jejunojejunostomy is performed in some instances. Enteric continuity following total gastrectomy is similar to that following Billroth II gastrojejunostomy, except that an anastomosis is created between the esophagus (instead of the remnant stomach) and the jejunum. Roux-en-Y esophagojejunostomy with end-to-side anastomosis is preferred nowadays (Fig 1d) (10). The closure of the duodenal stump and the jejunojejunostomy must be followed up.
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Figure 1a. Drawings illustrate anastomoses created following gastrectomy. (a) In Billroth I gastroduodenostomy, a partial gastrectomy (antrectomy) is performed and an end-to-end anastomosis is created between the remnant stomach (S) and the duodenum (D). In Hofmeister modification, usually the lesser curvature aspect of the cut end of the stomach is partially closed (arrowheads) and an anastomosis is created on the greater curvature side (arrow). (b, c) In Billroth II gastrojejunostomy, the duodenal stump (arrowheads) is closed and an anastomosis is created between the remnant stomach (S) and the jejunum (J). The type of anastomosis and the placement of the anastomotic loop can vary. The afferent loop (A) is shorter with retrocolic gastrojejunostomy (b) than with antecolic gastrojejunostomy (c). In some instances, a side-to-side anastomosis is also created between the two jejunal limbs (arrow in c). C = colon, E = efferent limb. (d) A Roux-en-Y procedure is the most commonly used reconstruction method following total gastrectomy. End-to-side esophagojejunostomy (straight solid arrows) with the blind end of the proximal jejunal limb (open arrow) and end-to-side jejunojejunostomy (curved arrow) are preferred nowadays. The closure of the duodenal stump (arrowheads) must be followed up. A = afferent limb, C = colon, E = efferent limb.
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Figure 1b. Drawings illustrate anastomoses created following gastrectomy. (a) In Billroth I gastroduodenostomy, a partial gastrectomy (antrectomy) is performed and an end-to-end anastomosis is created between the remnant stomach (S) and the duodenum (D). In Hofmeister modification, usually the lesser curvature aspect of the cut end of the stomach is partially closed (arrowheads) and an anastomosis is created on the greater curvature side (arrow). (b, c) In Billroth II gastrojejunostomy, the duodenal stump (arrowheads) is closed and an anastomosis is created between the remnant stomach (S) and the jejunum (J). The type of anastomosis and the placement of the anastomotic loop can vary. The afferent loop (A) is shorter with retrocolic gastrojejunostomy (b) than with antecolic gastrojejunostomy (c). In some instances, a side-to-side anastomosis is also created between the two jejunal limbs (arrow in c). C = colon, E = efferent limb. (d) A Roux-en-Y procedure is the most commonly used reconstruction method following total gastrectomy. End-to-side esophagojejunostomy (straight solid arrows) with the blind end of the proximal jejunal limb (open arrow) and end-to-side jejunojejunostomy (curved arrow) are preferred nowadays. The closure of the duodenal stump (arrowheads) must be followed up. A = afferent limb, C = colon, E = efferent limb.
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Figure 1c. Drawings illustrate anastomoses created following gastrectomy. (a) In Billroth I gastroduodenostomy, a partial gastrectomy (antrectomy) is performed and an end-to-end anastomosis is created between the remnant stomach (S) and the duodenum (D). In Hofmeister modification, usually the lesser curvature aspect of the cut end of the stomach is partially closed (arrowheads) and an anastomosis is created on the greater curvature side (arrow). (b, c) In Billroth II gastrojejunostomy, the duodenal stump (arrowheads) is closed and an anastomosis is created between the remnant stomach (S) and the jejunum (J). The type of anastomosis and the placement of the anastomotic loop can vary. The afferent loop (A) is shorter with retrocolic gastrojejunostomy (b) than with antecolic gastrojejunostomy (c). In some instances, a side-to-side anastomosis is also created between the two jejunal limbs (arrow in c). C = colon, E = efferent limb. (d) A Roux-en-Y procedure is the most commonly used reconstruction method following total gastrectomy. End-to-side esophagojejunostomy (straight solid arrows) with the blind end of the proximal jejunal limb (open arrow) and end-to-side jejunojejunostomy (curved arrow) are preferred nowadays. The closure of the duodenal stump (arrowheads) must be followed up. A = afferent limb, C = colon, E = efferent limb.
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Figure 1d. Drawings illustrate anastomoses created following gastrectomy. (a) In Billroth I gastroduodenostomy, a partial gastrectomy (antrectomy) is performed and an end-to-end anastomosis is created between the remnant stomach (S) and the duodenum (D). In Hofmeister modification, usually the lesser curvature aspect of the cut end of the stomach is partially closed (arrowheads) and an anastomosis is created on the greater curvature side (arrow). (b, c) In Billroth II gastrojejunostomy, the duodenal stump (arrowheads) is closed and an anastomosis is created between the remnant stomach (S) and the jejunum (J). The type of anastomosis and the placement of the anastomotic loop can vary. The afferent loop (A) is shorter with retrocolic gastrojejunostomy (b) than with antecolic gastrojejunostomy (c). In some instances, a side-to-side anastomosis is also created between the two jejunal limbs (arrow in c). C = colon, E = efferent limb. (d) A Roux-en-Y procedure is the most commonly used reconstruction method following total gastrectomy. End-to-side esophagojejunostomy (straight solid arrows) with the blind end of the proximal jejunal limb (open arrow) and end-to-side jejunojejunostomy (curved arrow) are preferred nowadays. The closure of the duodenal stump (arrowheads) must be followed up. A = afferent limb, C = colon, E = efferent limb.
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Postoperative anatomic changes following gastrectomy can usually be identified on consecutive CT scans. On CT scans obtained following Billroth I gastroduodenostomy (Fig 2), metallic surgical staples frequently indicate that Hofmeister modification has been performed (Fig 2a), and the duodenum is seen brought anteriorly to the gastroduodenal anastomosis (Fig 2b). However, once the duodenum resumes its normal position in the right subhepatic and peripancreatic space, CT findings may be very similar to those in a patient who has not undergone surgery (Fig 2c). In patients who have undergone Billroth II gas-trojejunostomy (Figs 3, 4), the gastrojejunostomy can be located on CT scans by following the course of the remnant stomach. In cases of loop-type reconstruction, the two jejunal limbs brought up to the anastomosis are seen either posterior (Fig 3) or anterior (Fig 4) to the transverse colon, which is usually filled with gas and feces. One of the jejunal limbs is the afferent limb, and the other is the efferent limb. Because the duodenum has been retained in its own bed, it serves as a landmark to help locate the afferent limb; the limb of the jejunal loop that is continuous with the duodenum and posterior to the superior mesenteric vessels can be assumed to be an afferent loop. The efferent limb has a more complex course and is difficult to follow. The duodenal stump is seen in the right subhepatic space (Fig 4c). Frequently, metallic suture material indicates the stump. Metallic surgical staples are commonly used in total gastrectomy with esophagojejunostomy and clearly indicate the anastomotic site at CT (Fig 5a). CT shows the jejunal loop, characterized by the valvulae conniventes, brought up to the anastomosis. Also, metallic suture material may be seen at the blind proximal jejunal stump (Fig 5b). Otherwise, CT scans obtained following total gastrectomy may appear quite similar to those obtained following Billroth II gastrojejunostomy.
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Figure 2a. Postoperative CT anatomy following Billroth I gastroduodenostomy. (a) CT scan shows a fluid-filled remnant stomach (S) posterior to the transverse colon (C), which is filled with gas and feces. Metallic suture material indicating Hofmeister modification is seen on the lesser curvature side of the remnant stomach (arrowhead). (b) CT scan shows the duodenum (D) brought anteriorly to the gastroduodenal anastomosis (solid arrow), which can be indirectly localized by noting the metallic suture material (arrowhead). Note also the small duodenal fold in the subhepatic space (open arrow) and the absence of thick pyloric muscle in that region. (c) CT scan shows that the duodenum (D) has resumed its normal position in the right subhepatic and peripancreatic space just distal to the anastomosis. This finding is similar to that in a patient who has not undergone surgery.
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Figure 2b. Postoperative CT anatomy following Billroth I gastroduodenostomy. (a) CT scan shows a fluid-filled remnant stomach (S) posterior to the transverse colon (C), which is filled with gas and feces. Metallic suture material indicating Hofmeister modification is seen on the lesser curvature side of the remnant stomach (arrowhead). (b) CT scan shows the duodenum (D) brought anteriorly to the gastroduodenal anastomosis (solid arrow), which can be indirectly localized by noting the metallic suture material (arrowhead). Note also the small duodenal fold in the subhepatic space (open arrow) and the absence of thick pyloric muscle in that region. (c) CT scan shows that the duodenum (D) has resumed its normal position in the right subhepatic and peripancreatic space just distal to the anastomosis. This finding is similar to that in a patient who has not undergone surgery.
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Figure 2c. Postoperative CT anatomy following Billroth I gastroduodenostomy. (a) CT scan shows a fluid-filled remnant stomach (S) posterior to the transverse colon (C), which is filled with gas and feces. Metallic suture material indicating Hofmeister modification is seen on the lesser curvature side of the remnant stomach (arrowhead). (b) CT scan shows the duodenum (D) brought anteriorly to the gastroduodenal anastomosis (solid arrow), which can be indirectly localized by noting the metallic suture material (arrowhead). Note also the small duodenal fold in the subhepatic space (open arrow) and the absence of thick pyloric muscle in that region. (c) CT scan shows that the duodenum (D) has resumed its normal position in the right subhepatic and peripancreatic space just distal to the anastomosis. This finding is similar to that in a patient who has not undergone surgery.
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Figure 3a. Postoperative CT anatomy following Billroth II retrocolic loop gastrojejunostomy. (a) CT scan shows a small remnant stomach (S), the gastrojejunal anastomosis (arrow), and the two jejunal limbs (A = afferent limb, E = efferent limb) brought up to the anastomosis posterior to the collapsed transverse colon (C). Metallic suture material on the lesser curvature side of the remnant stomach (arrowhead) indicates Hofmeister modification. Note the rim-enhancing mass in the liver, a finding that suggests metastasis. (b, c) Serial CT scans show the relatively short afferent jejunal limb (arrowhead), which approaches the region of the aortomesenteric root. The course of the efferent limb (open arrows) is more complex and difficult to follow. The duodenal stump, the blind end of the afferent limb (solid arrow in c), is noted in the right subhepatic space. (d) CT scan shows the third portion of the duodenum (arrow), which serves as a landmark to help locate the afferent limb (arrowhead). The afferent limb is continuous with the duodenum.
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Figure 3b. Postoperative CT anatomy following Billroth II retrocolic loop gastrojejunostomy. (a) CT scan shows a small remnant stomach (S), the gastrojejunal anastomosis (arrow), and the two jejunal limbs (A = afferent limb, E = efferent limb) brought up to the anastomosis posterior to the collapsed transverse colon (C). Metallic suture material on the lesser curvature side of the remnant stomach (arrowhead) indicates Hofmeister modification. Note the rim-enhancing mass in the liver, a finding that suggests metastasis. (b, c) Serial CT scans show the relatively short afferent jejunal limb (arrowhead), which approaches the region of the aortomesenteric root. The course of the efferent limb (open arrows) is more complex and difficult to follow. The duodenal stump, the blind end of the afferent limb (solid arrow in c), is noted in the right subhepatic space. (d) CT scan shows the third portion of the duodenum (arrow), which serves as a landmark to help locate the afferent limb (arrowhead). The afferent limb is continuous with the duodenum.
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Figure 3c. Postoperative CT anatomy following Billroth II retrocolic loop gastrojejunostomy. (a) CT scan shows a small remnant stomach (S), the gastrojejunal anastomosis (arrow), and the two jejunal limbs (A = afferent limb, E = efferent limb) brought up to the anastomosis posterior to the collapsed transverse colon (C). Metallic suture material on the lesser curvature side of the remnant stomach (arrowhead) indicates Hofmeister modification. Note the rim-enhancing mass in the liver, a finding that suggests metastasis. (b, c) Serial CT scans show the relatively short afferent jejunal limb (arrowhead), which approaches the region of the aortomesenteric root. The course of the efferent limb (open arrows) is more complex and difficult to follow. The duodenal stump, the blind end of the afferent limb (solid arrow in c), is noted in the right subhepatic space. (d) CT scan shows the third portion of the duodenum (arrow), which serves as a landmark to help locate the afferent limb (arrowhead). The afferent limb is continuous with the duodenum.
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Figure 3d. Postoperative CT anatomy following Billroth II retrocolic loop gastrojejunostomy. (a) CT scan shows a small remnant stomach (S), the gastrojejunal anastomosis (arrow), and the two jejunal limbs (A = afferent limb, E = efferent limb) brought up to the anastomosis posterior to the collapsed transverse colon (C). Metallic suture material on the lesser curvature side of the remnant stomach (arrowhead) indicates Hofmeister modification. Note the rim-enhancing mass in the liver, a finding that suggests metastasis. (b, c) Serial CT scans show the relatively short afferent jejunal limb (arrowhead), which approaches the region of the aortomesenteric root. The course of the efferent limb (open arrows) is more complex and difficult to follow. The duodenal stump, the blind end of the afferent limb (solid arrow in c), is noted in the right subhepatic space. (d) CT scan shows the third portion of the duodenum (arrow), which serves as a landmark to help locate the afferent limb (arrowhead). The afferent limb is continuous with the duodenum.
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Figure 4a. Postoperative CT anatomy following Billroth II antecolic loop gastrojejunostomy. (a) CT scan obtained following bowel opacification shows the remnant stomach (S) partially filled with orally administered contrast material. (b) CT scan shows the distal end of the stomach (S) and jejunal loop (J) brought up to the gastrojejunal anastomosis anterior to the transverse colon (C), which is filled with gas and feces. (c-e) Serial CT scans show the long afferent jejunal limb (A) filled with oral contrast material. The course of the efferent limb is more complex and difficult to follow. The duodenal stump (arrowheads in c) is noted in the right subhepatic space. (f) CT scan shows the third portion of the duodenum (arrows), which serves as a landmark to help locate the afferent limb. The afferent limb is continuous with the duodenum.
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Figure 4b. Postoperative CT anatomy following Billroth II antecolic loop gastrojejunostomy. (a) CT scan obtained following bowel opacification shows the remnant stomach (S) partially filled with orally administered contrast material. (b) CT scan shows the distal end of the stomach (S) and jejunal loop (J) brought up to the gastrojejunal anastomosis anterior to the transverse colon (C), which is filled with gas and feces. (c-e) Serial CT scans show the long afferent jejunal limb (A) filled with oral contrast material. The course of the efferent limb is more complex and difficult to follow. The duodenal stump (arrowheads in c) is noted in the right subhepatic space. (f) CT scan shows the third portion of the duodenum (arrows), which serves as a landmark to help locate the afferent limb. The afferent limb is continuous with the duodenum.
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Figure 4c. Postoperative CT anatomy following Billroth II antecolic loop gastrojejunostomy. (a) CT scan obtained following bowel opacification shows the remnant stomach (S) partially filled with orally administered contrast material. (b) CT scan shows the distal end of the stomach (S) and jejunal loop (J) brought up to the gastrojejunal anastomosis anterior to the transverse colon (C), which is filled with gas and feces. (c-e) Serial CT scans show the long afferent jejunal limb (A) filled with oral contrast material. The course of the efferent limb is more complex and difficult to follow. The duodenal stump (arrowheads in c) is noted in the right subhepatic space. (f) CT scan shows the third portion of the duodenum (arrows), which serves as a landmark to help locate the afferent limb. The afferent limb is continuous with the duodenum.
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Figure 4d. Postoperative CT anatomy following Billroth II antecolic loop gastrojejunostomy. (a) CT scan obtained following bowel opacification shows the remnant stomach (S) partially filled with orally administered contrast material. (b) CT scan shows the distal end of the stomach (S) and jejunal loop (J) brought up to the gastrojejunal anastomosis anterior to the transverse colon (C), which is filled with gas and feces. (c-e) Serial CT scans show the long afferent jejunal limb (A) filled with oral contrast material. The course of the efferent limb is more complex and difficult to follow. The duodenal stump (arrowheads in c) is noted in the right subhepatic space. (f) CT scan shows the third portion of the duodenum (arrows), which serves as a landmark to help locate the afferent limb. The afferent limb is continuous with the duodenum.
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Figure 4e. Postoperative CT anatomy following Billroth II antecolic loop gastrojejunostomy. (a) CT scan obtained following bowel opacification shows the remnant stomach (S) partially filled with orally administered contrast material. (b) CT scan shows the distal end of the stomach (S) and jejunal loop (J) brought up to the gastrojejunal anastomosis anterior to the transverse colon (C), which is filled with gas and feces. (c-e) Serial CT scans show the long afferent jejunal limb (A) filled with oral contrast material. The course of the efferent limb is more complex and difficult to follow. The duodenal stump (arrowheads in c) is noted in the right subhepatic space. (f) CT scan shows the third portion of the duodenum (arrows), which serves as a landmark to help locate the afferent limb. The afferent limb is continuous with the duodenum.
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Figure 4f. Postoperative CT anatomy following Billroth II antecolic loop gastrojejunostomy. (a) CT scan obtained following bowel opacification shows the remnant stomach (S) partially filled with orally administered contrast material. (b) CT scan shows the distal end of the stomach (S) and jejunal loop (J) brought up to the gastrojejunal anastomosis anterior to the transverse colon (C), which is filled with gas and feces. (c-e) Serial CT scans show the long afferent jejunal limb (A) filled with oral contrast material. The course of the efferent limb is more complex and difficult to follow. The duodenal stump (arrowheads in c) is noted in the right subhepatic space. (f) CT scan shows the third portion of the duodenum (arrows), which serves as a landmark to help locate the afferent limb. The afferent limb is continuous with the duodenum.
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Figure 5a. Postoperative CT anatomy following total gastrectomy with Roux-en-Y esophagojejunostomy. (a) CT scan shows surgical staples at the end of the esophagus (arrowhead), a finding that clearly indicates the esophagojejunostomy site. (b) CT scan shows the jejunal loop (arrowheads), characterized by the valvulae conniventes, brought up to the anastomosis. Metallic suture material at the blind proximal jejunal stump is also noted (arrow). (c, d) Serial CT scans show a relatively short afferent limb (arrowheads) with its blind end (duodenal stump) (open arrow in c) in the right subhepatic space. Metallic suture material (solid arrow in c) clearly indicates the duodenal stump. Note also the apparent wall thickening at the jejunojejunostomy site (arrow in d) and dilatation of the afferent loop with fluid attenuation. These findings are consistent with afferent loop syndrome. C = colon, E = efferent limb.
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Figure 5b. Postoperative CT anatomy following total gastrectomy with Roux-en-Y esophagojejunostomy. (a) CT scan shows surgical staples at the end of the esophagus (arrowhead), a finding that clearly indicates the esophagojejunostomy site. (b) CT scan shows the jejunal loop (arrowheads), characterized by the valvulae conniventes, brought up to the anastomosis. Metallic suture material at the blind proximal jejunal stump is also noted (arrow). (c, d) Serial CT scans show a relatively short afferent limb (arrowheads) with its blind end (duodenal stump) (open arrow in c) in the right subhepatic space. Metallic suture material (solid arrow in c) clearly indicates the duodenal stump. Note also the apparent wall thickening at the jejunojejunostomy site (arrow in d) and dilatation of the afferent loop with fluid attenuation. These findings are consistent with afferent loop syndrome. C = colon, E = efferent limb.
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Figure 5c. Postoperative CT anatomy following total gastrectomy with Roux-en-Y esophagojejunostomy. (a) CT scan shows surgical staples at the end of the esophagus (arrowhead), a finding that clearly indicates the esophagojejunostomy site. (b) CT scan shows the jejunal loop (arrowheads), characterized by the valvulae conniventes, brought up to the anastomosis. Metallic suture material at the blind proximal jejunal stump is also noted (arrow). (c, d) Serial CT scans show a relatively short afferent limb (arrowheads) with its blind end (duodenal stump) (open arrow in c) in the right subhepatic space. Metallic suture material (solid arrow in c) clearly indicates the duodenal stump. Note also the apparent wall thickening at the jejunojejunostomy site (arrow in d) and dilatation of the afferent loop with fluid attenuation. These findings are consistent with afferent loop syndrome. C = colon, E = efferent limb.
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Figure 5d. Postoperative CT anatomy following total gastrectomy with Roux-en-Y esophagojejunostomy. (a) CT scan shows surgical staples at the end of the esophagus (arrowhead), a finding that clearly indicates the esophagojejunostomy site. (b) CT scan shows the jejunal loop (arrowheads), characterized by the valvulae conniventes, brought up to the anastomosis. Metallic suture material at the blind proximal jejunal stump is also noted (arrow). (c, d) Serial CT scans show a relatively short afferent limb (arrowheads) with its blind end (duodenal stump) (open arrow in c) in the right subhepatic space. Metallic suture material (solid arrow in c) clearly indicates the duodenal stump. Note also the apparent wall thickening at the jejunojejunostomy site (arrow in d) and dilatation of the afferent loop with fluid attenuation. These findings are consistent with afferent loop syndrome. C = colon, E = efferent limb.
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Postoperative Complications
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Peri- and postoperative morbidity is common following gastric cancer surgery because resections are extensive. In general, most of the complications occurring in the immediate postoperative period are related to infection or to problems with surgical technique. The vast majority of these complications are due to the nature and inherent risk of surgical intervention, but iatrogenic problems have also been recognized.
Anastomotic Leakage
Common to almost all reconstructive gastrointestinal surgery is the risk of an anastomotic leak, which can lead to a localized fluid collection or abscess in the surgical bed. Anastomotic leakage is most frequently seen in cases of total gastrectomy (10,11). CT can provide crucial information by demonstrating pneumoperitoneum, extraluminal accumulation of oral contrast material (Fig 6), and associated intraabdominal abscesses (7). However, pneumoperitoneum alone is an extremely common postoperative finding, and the extravasation of oral contrast material is infrequently seen in cases of small leaks. A localized fluid collection or abscess that is the only manifestation of an anastomotic leak may not be reliably differentiated from a transient postoperative serum collection with CT alone.
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Figure 6. Anastomotic leakage at gastrojejunostomy in a 57-year-old man who had undergone partial gastrectomy. CT scan obtained following bowel opacification with oral administration of gastrografin 2 weeks after surgery shows an extraluminal accumulation of contrast material (arrows) in the superior recess of the lesser sac, a finding that suggests a leak at the gastrojejunostomy site.
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In screening for evidence of an anastomotic leak, it is important to remember that, because of the postoperative changes in normal anatomic barriers due to transection of peritoneal ligaments and mesenteries during surgery, postoperative fluid collections or abscesses may develop in unusual or unexpected locations. During gastrectomy, gastrocolic and gastrosplenic ligaments are transected to mobilize the greater curvature of the stomach. This establishes communication between the lesser sac and the left subphrenic space. In addition, the gastrohepatic ligament is partially transected to mobilize the distal stomach and the first portion of the duodenum, resulting in communication between the lesser sac and the gastrohepatic and gastrosplenic spaces. Therefore, an anastomotic leak from esophagojejunostomy or gastrojejunostomy may result in an abscess that occupies the postoperative "neocompartment" (eg, the lesser sac and the left subphrenic, gastrohepatic, and gastrosplenic spaces) (Fig 7) (12). When an abscess is small, it typically coalesces in the left subphrenic area owing to negative intraabdominal pressure beneath the diaphragm related to respiration. Associated abnormalities such as pleural effusion and basal pulmonary consolidations often accompany subphrenic abscesses.
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Figure 7a. Postoperative abscess due to an anastomotic leak at gastrojejunostomy in a 63-year-old man who had undergone partial gastrectomy. (a) CT scan obtained 10 days after surgery shows an abscess in the postoperative neocompartment, which includes the superior recess of the lesser sac (small straight arrows), the gastrosplenic spaces (curved arrow), and the left subphrenic space (large straight arrow). There is mottled gas collection within the abscess (arrowheads). (b) Abscessogram shows a fistula to the jejunum, a finding that suggests a leak at the gastrojejunostomy site. The patient had persistent fever before undergoing CT and improved after percutaneous drainage of the abscess.
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Figure 7b. Postoperative abscess due to an anastomotic leak at gastrojejunostomy in a 63-year-old man who had undergone partial gastrectomy. (a) CT scan obtained 10 days after surgery shows an abscess in the postoperative neocompartment, which includes the superior recess of the lesser sac (small straight arrows), the gastrosplenic spaces (curved arrow), and the left subphrenic space (large straight arrow). There is mottled gas collection within the abscess (arrowheads). (b) Abscessogram shows a fistula to the jejunum, a finding that suggests a leak at the gastrojejunostomy site. The patient had persistent fever before undergoing CT and improved after percutaneous drainage of the abscess.
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Duodenal Stump Leakage
Leakage from the duodenal stump has been the most worrisome technical complication of Billroth II reconstruction following gastric resection or total gastrectomy (10,13). Leakage of bile or pancreatic juice causes localized peritoneal irritation, and subsequent bacterial infection may further aggravate the postoperative course unless treated properly. Duodenal stump leakage usually results in a postoperative fluid collection or abscess located in the right subhepatic space and often extending to the peripancreatic space. The widespread use of CT has facilitated diagnosis of duodenal stump leakage by demonstrating postoperative fluid collections or abscesses in these spaces surrounding the stump. Furthermore, in some instances, direct communication between the abscess and the duodenum via a narrow fistulous tract may be seen at abscessography (Fig 8).
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Figure 8a. Postoperative abscess due to duodenal stump leakage in a 62-year-old woman who had undergone total gastrectomy. (a) Unenhanced CT scan obtained 2 weeks after surgery shows a localized postoperative abscess (straight solid black arrows) in the peripancreatic area surrounding the pancreatic head (open arrow) and duodenal stump (curved arrow). A surgical drain (arrowhead) had been placed in the area but was considered ineffective. There is also a small fluid collection in the left paracolic gutter (white arrow). (b) Abscessogram obtained with administration of contrast material through the drainage catheter demonstrates a fistula to the duodenum, a finding that suggests a leak.
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Figure 8b. Postoperative abscess due to duodenal stump leakage in a 62-year-old woman who had undergone total gastrectomy. (a) Unenhanced CT scan obtained 2 weeks after surgery shows a localized postoperative abscess (straight solid black arrows) in the peripancreatic area surrounding the pancreatic head (open arrow) and duodenal stump (curved arrow). A surgical drain (arrowhead) had been placed in the area but was considered ineffective. There is also a small fluid collection in the left paracolic gutter (white arrow). (b) Abscessogram obtained with administration of contrast material through the drainage catheter demonstrates a fistula to the duodenum, a finding that suggests a leak.
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Intraabdominal Bleeding
Hemorrhage into the surgical field and various compartments of the peritoneal cavity represents a serious complication of gastrointestinal surgery. It may originate from inadequate vascular ligation or hemostasis, a torn spleen, or hemorrhagic pancreatitis (10,13). The presence of intraabdominal hemorrhage manifests clinically as oozing of blood through the surgical drains or incision along with hypotension. CT may also be used to document the existence and location of intraabdominal hematomas. Although intraabdominal hemorrhage can simulate the appearance and distribution of ascitic fluid, it has high attenuation values (20–40 HU) in the acute stage (7). Still, it is sometimes difficult to distinguish a chronic hematoma from other fluid collections or abscess.
Wound Complications
The incision is easily recognized at CT as a band of increased attenuation between the opposed margins of transected skin, subcutaneous fat, abdominal wall muscles, and fascial and peritoneal planes. It may become infected, resulting in inflammation or necrosis of the sutured structures as well as accumulation of pus at the center of or immediately adjacent to the incision. Although the presence of wound infection is often diagnosed clinically, CT can facilitate early detection by demonstrating small collections of fluid or gas deep within the incision and neighboring tissues (7). Loosening of the sutures and wound dehiscence may be performed.
Although minimal self-limited hemorrhage from the site of incision is not uncommon during the immediate postoperative period, slipped ligatures or postoperative coagulation problems may result in significant bleeding into the abdominal wall. The correct CT diagnosis can be made by virtue of asymmetric enlargement and increased attenuation of the abdominal wall muscles.
Other Complications
Acute postoperative pancreatitis is seen primarily in conjunction with a pancreatic injury that occurs during gastrectomy or in cases of invasion of the pancreas or spleen by gastric carcinoma that require partial pancreatectomy or splenectomy. The CT features of postoperative pancreatitis include segmental or diffuse enlargement of the pancreas, pseudocyst formation, and inflammatory changes or a fluid collection in the left anterior pararenal space (10).
A rare but alarming cause of postoperative abscess is intraabdominal retention of surgical foreign bodies, the most common of which is a laparotomy sponge owing to its frequent use and the depth of the cavities into which it is placed. Most institutions now use only sponges that contain radiopaque markers and can therefore be detected at conventional radiography. At CT, retained surgical sponges generally manifest as a well-defined mass with a thick wall, internal heterogeneous areas of increased attenuation with a wavy or striped appearance, and, occasionally, mottled calcifications and gas bubbles (14).
One of the most serious complications of gastric resection is diffuse peritonitis. This complication may be due to several causes, including contamination or bowel spillage during surgery and leakage from the duodenal stump or gastrojejunal anastomosis during the postoperative period (13).
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Tumor Recurrence
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Although tumor recurrence has a poor prognosis (15), early identification is helpful because it might allow patients with minimal adenopathy or small recurrent masses to respond better to chemotherapy or radiation therapy (16). In screening for the presence of recurrent disease, it is important to understand the means by which cancer can spread from the stomach to other sites (ie, dissemination, contiguous invasion, lymphatic or hematogenous spread) (1). Because postoperative changes frequently mimic tumor recurrence, it is necessary that radiologists be familiar with the common CT patterns of tumor recurrence.
Local Recurrence
Local recurrence of gastric cancer most commonly involves the region of the gastric stump or anastomosis. Transverse CT displays the change in anastomotic relationships secondary to the surgical procedure. Recurrence at the gastric stump or anastomosis manifests as localized bowel wall thickening at CT (Figs 9, 10). However, although determining the degree and extent of bowel wall thickening at CT is important for the diagnosis of tumor recurrence, the main problem is lack of specificity. Potential sources of erroneous interpretation include improperly distended bowel loops, surgical plication, bowel adhesion, and stomal polypoid hypertrophic gastritis (4).
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Figure 9. Local tumor recurrence in a 48-year-old woman who had undergone Billroth I partial gastrectomy. CT scan shows recurrent tumor manifesting as strongly contrast material-enhanced irregular mucosal thickening in the remnant stomach (arrows). Retention of a large amount of food material in the remnant stomach (*) indicates gastric outlet obstruction caused by recurrent tumor. Tumor recurrence was confirmed at histologic analysis of material obtained at endoscopic biopsy.
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Figure 10a. Local tumor recurrence with afferent loop syndrome in a 64-year-old woman who had undergone subtotal gastrectomy. (a) CT scan shows local tumor recurrence involving a gastrojejunal anastomosis and the efferent limb of the anastomotic loop (arrow). Dilatation of the afferent limb is also seen (*). Tumor recurrence was confirmed at histologic analysis of material obtained at endoscopic biopsy. (b) CT scan obtained at the level of the left renal hilum shows distention of the afferent loop with fluid attenuation (*). Hydronephrosis involving the right kidney is also noted (arrowhead), a finding that is considered to be due to periureteral metastasis.
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Figure 10b. Local tumor recurrence with afferent loop syndrome in a 64-year-old woman who had undergone subtotal gastrectomy. (a) CT scan shows local tumor recurrence involving a gastrojejunal anastomosis and the efferent limb of the anastomotic loop (arrow). Dilatation of the afferent limb is also seen (*). Tumor recurrence was confirmed at histologic analysis of material obtained at endoscopic biopsy. (b) CT scan obtained at the level of the left renal hilum shows distention of the afferent loop with fluid attenuation (*). Hydronephrosis involving the right kidney is also noted (arrowhead), a finding that is considered to be due to periureteral metastasis.
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Whereas small bowel obstruction in postoperative patients is usually caused by adhesive bands, CT not infrequently demonstrates small or large bowel obstruction due to local tumor recurrence following Billroth II gastrojejunostomy or total gastrectomy. Efferent jejunal loop obstruction may result from superficial tumor spread, whereas colonic obstruction may result from extraluminal extension with direct invasion of the transverse colon. Afferent loop syndrome sometimes develops in cases of tumor recurrence at the proximal afferent loop. CT shows marked distention of the afferent loop with fluid attenuation in a U-shaped configuration (Figs 5, 10).
Other common sites of local tumor recurrence include the pancreas and abdominal incision. However, local recurrence involving the pancreas may be indistinguishable at CT from a primary pancreatic tumor or an enlarged peripancreatic lymph node, and postoperative fibrotic changes can mimic tumor recurrence at the abdominal incision (4,15).
Lymph Node Metastases
Lymph node metastases occur in 90% of patients with untreated advanced gastric cancer (1) and also comprise the majority of tumor recurrences, although their exact prevalence is unknown. Because regional perigastric lymph nodes are usually dissected and excised during radical surgery, nodal metastasis in recurrent gastric carcinoma usually involves retroperitoneal nodes. The most common locations of metastatic lymphadenopathy include the region along the common hepatic artery, celiac axis, and hepatoduodenal ligament (15) and the periaortic region (5). Lymph node metastases can be easily diagnosed when they are large enough or conglomerated at CT; however, small solitary or focal lymph node metastases may not be detected or differentiated from metastasis-negative nodes. Frequently, metastatic lymphadenopathy along the common hepatic artery, celiac axis, or hepatoduodenal ligament causes obstruction of the extrahepatic bile duct due to extrinsic compression and may result in moderate to severe dilatation of the intrahepatic bile duct (Fig 11).
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Figure 11a. Lymph node metastasis in a 55-year-old woman who had undergone radical surgery. Consecutive CT scans show conglomerated metastatic lymph nodes in the left paraaortic (large solid arrows) and peripancreatic (small solid arrows) areas. Moderate dilatation of both intrahepatic bile ducts (arrowheads) was caused by the metastatic lymphadenopathy. Small metastatic nodules are also seen in the liver (open arrows).
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Figure 11b. Lymph node metastasis in a 55-year-old woman who had undergone radical surgery. Consecutive CT scans show conglomerated metastatic lymph nodes in the left paraaortic (large solid arrows) and peripancreatic (small solid arrows) areas. Moderate dilatation of both intrahepatic bile ducts (arrowheads) was caused by the metastatic lymphadenopathy. Small metastatic nodules are also seen in the liver (open arrows).
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Peritoneal Seeding
Gastrointestinal tumors tend to recur along the peritoneal surface due to spillage of tumor cells into the peritoneal cavity during surgery, retrograde leakage of tumor emboli in transected lymphatic vessels during the postoperative period, or seeding following full-thickness penetration of the bowel wall in local tumor recurrence (17). Ascites is one of the most common findings with these tumors, and ascitic fluid is often loculated or septated or may be absent in typical or dependent areas such as the pelvis. This malignant ascites (diffuse peritoneal carcinomatosis) is well depicted at CT (Fig 12). Of more recent interest is the rare diffuse involvement of the rectum (metastatic linitis plastica to the rectum) in affected patients. Although the prevalence of and routes for this type of rectal involvement are not well understood, one study found that the most common CT feature was concentric bowel wall thickening in a long (>10-cm) segment (Fig 13) (18).
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Figure 12. Peritoneal seeding in a 60-year-old man who had undergone radical surgery. CT scan shows complicated ascites with enhanced peritoneal thickening (arrows). There are small metastatic nodules in both periureteric spaces (arrowheads), resulting in bilateral hydronephrosis. Tumor recurrence was confirmed at histologic analysis of the ascitic fluid obtained at fine-needle aspiration.
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Figure 13. Metastatic linitis plastica to the rectum in a 47-year-old man who had undergone gastrectomy. CT scan shows concentric bowel wall thickening and mucosal enhancement in a long segment of the rectum (arrowheads). There is also thickening of the posterolateral wall of the urinary bladder (arrows). Proctoscopy and cystoscopy helped confirm tumor infiltration to the rectum and bladder.
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Hematogenous Metastases
Blood-borne metastases from gastric carcinoma are most frequently seen in the liver (1,15). Because the lesions are usually hypovascular, the optimal CT strategy is helical scanning during the portal venous phase of enhancement to improve lesion conspicuity by increasing the attenuation of normal liver (Figs 3, 11, 14). The sensitivity of this imaging procedure is more than 90% for the detection of lesions greater than 1 cm (19). Occasionally, rim enhancement of a hypoattenuating metastasis can be seen. Other, less common sites of hematogenous spread include the lungs, adrenal glands, and ovaries. Krukenberg tumors are often large and bilateral and manifest as adnexal solid masses with heterogeneous contrast enhancement (Fig 15) (1).
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Figure 14a. Hepatic metastasis in a 59-year-old man who had undergone gastrectomy. CT scans obtained during the hepatic arterial phase (a) and portal venous phase (b) show a large, lobulated metastatic mass in the right lobe of the liver (arrow), hypertrophy of the right hepatic artery (arrowheads in a), and malignant portal vein thrombosis (arrowheads in b) contiguous with the metastasis.
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Figure 14b. Hepatic metastasis in a 59-year-old man who had undergone gastrectomy. CT scans obtained during the hepatic arterial phase (a) and portal venous phase (b) show a large, lobulated metastatic mass in the right lobe of the liver (arrow), hypertrophy of the right hepatic artery (arrowheads in a), and malignant portal vein thrombosis (arrowheads in b) contiguous with the metastasis.
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Figure 15. Krukenberg tumor in a 48-year-old woman who had undergone radical surgery. CT scan shows a mixed cystic and solid tumor in the right lower quadrant (arrows), a finding that suggests the possibility of Krukenberg tumor. This finding was confirmed at histologic analysis of the excised mass.
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Conclusions
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Abstract
LEARNING OBJECTIVES
